testscript.py: Add script parsing test
testscript.py: Add script parsing test

jgarzik/python-bitcoinlib,daedalus/python-bitcoin_r,jgarzik/pynode,petertodd/dust-b-gone,robertsdotpm/python-bitcoinlib,petertodd/tx-flood-attack,petertodd/stealth-addresses-ref-implementation,daedalus/pynode